Modeling and Control of a Three-Phase Four-Switch PWM Voltage-Source Rectifier in d-q Synchronous Frame

Controller design for six-switch pulse width-modulated (PWM) voltage source rectifiers (VSRs) is often accomplished in the rotating d-q frame coordinates in order to achieve a high-performance control. In contrast, the development of a d-q frame controller for a four-switch PWM VSR is rarely reported in the literature. In this regard, this paper introduces a control design approach in rotating d-q frame for the four-switch PWM VSRs. For this purpose, a mathematical model of the four-switch PWM VSR in rotating d-q frame is first derived. Its success is relied on performing a so-called "reduced Park Transformation" on switching functions. The derived model shares much structural property with that of a six-switch VSR. Then, two d-q frame current controller designs, input-output feedback linearization (IOFL) and linear proportional-plus-integral (LPI) control, are performed based on the derived model as application examples. Their effectiveness is verified via computer simulation and hardware experiment. Responses of an LPI a-b-c frame controller originated from the sixswitch VSR are also documented for comparative study. Test results evidence the superiority of the d-q frame controllers.